Natural observation by humans of a scene includes a series of fixations and saccades, which are generally spread (not uniformly) over the visual scene. Fixations are observations of a certain point in the visual field, leading to an accurately processed input spanning approximately two degrees of the fixation point. There are typically 3-4 fixations per second, with typical durations of 200-300 milliseconds. Saccades relocations of the point of fixation that change the point of fixation from an origination point to a different point, and generally last about 40 milliseconds or so (depending on the saccade amplitude).
Personal computing devices are ubiquitous in modern society, and are typically used to execute myriad user applications including, for example, word processing applications, personal entertainment applications, informational applications, audio, video and or still image applications and the like. Many such applications include one or more activation graphics which, when selected by the user, initiates a corresponding action within the user application. Eye movements of users viewing the display screen of such devices can be processed to allow for automatic activation of one or more such activation graphics during execution of a user application.